CHENGDU - Construction of supporting infrastructure for a cutting-edge solar telescope began Tuesday in Daocheng county in Southwest China's Sichuan province, marking a significant step toward a new era of high-resolution solar observation.
The 2.5-meter Wide-field and High-resolution Solar Telescope (WeHoST), a national research instrumentation project, is led by Nanjing University in collaboration with the Nanjing Institute of Astronomical Optics and Technology and the Yunnan Observatories, both under the Chinese Academy of Sciences.
The construction of the telescope officially began in 2022. Upon completion, it will be the world's largest axisymmetric solar telescope.
Strategically situated at an elevation of 4,700 meters on an unnamed mountain in Daocheng county, the chosen site boasts exceptional atmospheric stability and solar observation conditions.
This location is poised to become the world's highest solar observatory, providing a critical foundation for acquiring world-class observational data.
Construction of the supporting infrastructure and telescope assembly is scheduled for completion by the end of 2026, followed by comprehensive system commissioning and testing.
The telescope project promises unprecedented capabilities thanks to its combination of a wide field of view with high spatial resolution.
This unique configuration will enable multi-band imaging and magnetic field observations, which are essential for comprehensively investigating the origin and energy release mechanisms of major solar events, such as flares and coronal mass ejections.
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Scientists anticipate that the telescope will lead to breakthrough discoveries on the origin and evolution of solar active regions, as well as the mechanisms driving solar eruptive phenomena.
By integrating data-driven simulations, scientists can study solar eruptive phenomena, propose the underlying physical laws, and provide a solid foundation for hazardous space weather forecasting, thereby safeguarding China's deep-space exploration and manned spaceflight missions, Fang Cheng, an academician of the Chinese Academy of Sciences, told Xinhua.
According to Fang, also a professor with Nanjing University's School of Astronomy and Space Science, this telescope can observe an area of some 300,000 square km on the solar surface, with a resolution of 100 km.
"Such resolution is equivalent to clearly seeing an object with the size of a coin at a distance of 50 km," he added.
According to Li Zhen, a senior engineer with Nanjing University's School of Astronomy and Space Science, WeHoST can switch between day and night optical paths in less than 10 minutes by using a flat mirror to change the optical path. This unique feature is expected to bring new discoveries to China's time-domain astronomy, including observations of supernovae, gamma-ray bursts, tidal disruption events of black holes, and stellar flares.
Li also revealed that when exposed to sunlight, WeHoST's primary mirror can receive up to 5,000 watts of heat, which is enough to bring one liter of water to the boiling point from room temperature in just a few seconds.
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To address this challenge, the back of the primary mirror is evenly equipped with over 100 air tubes, which spray cold air to carry away the solar energy absorbed by the mirror. The tube and the focus of the telescope are cooled effectively by controlling the temperature and flow rate of the refrigerant liquid.
The telescope project has also brought new opportunity to Daocheng county, a renowned tourist destination in Sichuan known for its breathtaking snow-capped mountains, glacial lakes and alpine meadows.
County head Yuan Bin explained that WeHoST will join Daocheng's Large High Altitude Air Shower Observatory (LHAASO), and the Piluo site, a large-scale Paleolithic archaeological site, to form an astronomical and archaeological cluster.
